public class Main {
    public static void main(String[] args) {
        MallardDuck mallard = new MallardDuck("绿色", 1.5);
        mallard.fly();
        mallard.quack();
        mallard.setHeavy(1.6);
        mallard.setHeavy("中等重量");

        RubberDuck rubber = new RubberDuck("黄色", 0.2);
        rubber.fly();
        rubber.quack();
        rubber.setHeavy(0.3);
        rubber.setHeavy(0.3, "千克");
    }
}